Break

Low cost and efficient adsorption of heavy metals from wastewater and thorough removal of adsorbent after water treatment has become the two essential needs. Hence, the main objective of a series of our studies is to develop an advanced acoustic-based method for activation of carbonaceous structures which can be effectively used for adsorption and easily removed from the aqueous solution. Biochar, the solid byproduct of pyrolysis with microporous carbonaceous structure, has been increasingly recognized as an efficient adsorbent for a vast number of pollutants. Magnetization, though eases the separation and reuse of biochar, significantly reduces its adsorption capacity to a comparatively much higher extent.. In this study, a hybrid post-pyrolysis modification was developed which sustained and even significantly increased the adsorption capacity of biochar. The process included i) structural modification of biochar under ultrasound waves, ii) magnetization with magnetite (Fe₃O₄) nanoparticles and iii) functionalization with 3-aminopropyl triethoxysilane (APTES). Low frequency ultrasound irradiation exfoliates and breaks apart the irregular graphite layers of biochar, and creates new/opens the blocked micropores, thus enhancing the biochar’s porosity. On the other hand, APTES stabilizes the nanoparticles on the biochar surface, while it participates in water treatment. Preliminary results showed that acoustic-based magnetic biochar exhibited a much greater ability to remove Ni and Pb, with 124% and 31% higher adsorption compared to raw biochar. This high performance can be attributed to the synergistic effect of ultrasound activation on increasing the porosity and surface area of biochar and its further interaction with amine functionalization using APTES.